Alcohol use disorders (AUDs) are prevalent among Veterans and result in significant physical and psychological burden. Among those who receive treatment for AUDs, 1 in 3 relapses to problematic drinking within one year of treatment. Thus, additional strategies are needed to enhance alcohol treatment outcomes. One promising approach involves providing concurrent treatment for a common complaint ? difficulty falling or staying asleep. As many as 63% of Veterans with AUDs report co-occurring symptoms of insomnia. Given the negative impact of insomnia on attention and emotion regulation, insomnia symptoms may decrease patients? abilities to attend to alcohol treatment and manage negative emotions that lead to craving and relapse. Moreover, approximately 50% of individuals with AUDs report using alcohol to help them sleep, making relapse more likely for those with no other tools or skills to help them sleep. Indeed, sleep disturbance has been identified as a risk factor for relapse among individuals in alcohol treatment. Thus, effective treatment of sleep problems may enhance alcohol treatment for a substantial number of individuals with AUDs. Cognitive Behavioral Therapy for Insomnia (CBTi) has been effective in reducing insomnia severity in individuals with AUDs; however, no investigations have examined the efficacy of CBTi delivered concurrently with AUD treatment to determine its impact on treatment engagement. This R21 aims to examine the feasibility, acceptability, and initial efficacy of a CBTi supplement to ongoing outpatient alcohol treatment at the VA. We will conduct a randomized pilot trial with 80 Veterans who meet DSM-5 criteria for AUD and the episodic criterion for Insomnia Disorder. Participants will be randomly assigned to a minimal-treatment (education) control involving sleep hygiene education in addition to treatment as usual (eTAU; n = 40) or TAU+CBTi (n = 40). Outcomes will be assessed at the end of the active intervention period (6 weeks) and 6 weeks post- intervention. Outcomes of interest include recruitment and retention rates, treatment satisfaction, percentage of abstinent days, percentage of heavy drinking days, alcohol-related consequences, use of alcohol as a sleep aid, sleep efficiency, ability to sustain attention, working memory, negative affect, and emotion regulation. Data analyses will focus on size of treatment effects. Results will inform an R01 application to examine the efficacy, cost-effectiveness, and potential mechanisms of CBTi in preventing or delaying relapse to problematic drinking among Veterans with insomnia and AUDs. This study will provide initial evidence that treatment of insomnia not only improves sleep but also allows participants to derive greater benefit from intensive outpatient alcohol treatment.